Method for producing trim strip assembly

ABSTRACT

A METHOD AND APPARATUS FOR PRODUCING A TRIM STRIP ASSEMBLY IS DISCLOSED. THE TRIM STRIP INCLUDES A THEMOPLASTIC BASE MEMBER, A SUPERIMPOSED STRIP, AND A PLASTIC TOP COATING. THE SUPERIMPOSED STRIP MAY BE OF PLASTIC, METAL OR FOIL. THE APPARATUS INCLUDES EXTRUDERS AND A DIE HAVING THREE PASSAGEWAYS. A FIRST PASSAGEWAY RECEIVES THE EXTRUDED BASE MEMBER, A SECOND PASSAGEWAY INTERSECTS THE FIRST PASSAGEWAY AND RECEIVES THE SUPERIMPOSED STRIP, AND A THRID PASSAGEWAY INTERSECTS THE SECOND PASSAGEWAY A PREDETERMINED DISTANCE FROM THE INTERSECTION OF THE FIRST AND SECOND PASSAGEWAYS.

C. E. FRIESNER METHOD FOR PRODUCING TRIM STRIP ASSEMBLY Dec. 18, 1973 Filed March 23, 1971 2 Shuts-Sheet 1 3 INVENTOR.

EHAHLEE E. FHIE SNER.

Dec. 18, 1973 c. E. FRIESNER 3,780,152

METHOD FOR PRODUCING TRIM STRIP ASSEMBLY Filed March 23, 1971 2 Sheets-Sheet I INVENTOR:

m -4- I CHARLEE E. FRJEENEH.

ATTYS.

United States Patent 3,780,152 METHOD FOR PRODUCING TRIM STRIP ASSEMBLY Charles E. Friesner, Pemberville, Ohio, assignor to Industrial Plastic Specialties Company, Chelsea, Mich. Filed Mar. 23, 1971, Ser. No. 127,168 Int. Cl. B29f 3/00 US. Cl. 264174 8 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for producing a trim strip assembly is disclosed. The trim strip includes a thermoplastic base member, a superimposed strip, and a plastic top coating. The superimposed strip may be of plastic, metal or foil. The apparatus includes extruders and a die having three passageways. A first passageway receives the extruded base member, a second passageway intersects the first passageway and receives the superimposed strip, and a third passageway intersects the second passageway a predetermined distance from the intersection of the first and second passageways.

BACKGROUND OF THE INVENTION The present invention relates to a trim strip assembly suitable for use on automobile exteriors, and to a process for producing such a trim strip.

For many years, the auto industry has made extensive use of metal trim strips to protect and enhance the exterior appearance of autos. Because of the cost of fabricating and attaching metal trim strips, auto manufacturers have attempted to substitute a composite plastic trim strip for such metal trim strips.

In general, prior art plastic trim strips have been produced by encapsulating a thin ribbon of metal foil within a transparent thermoplastic material. The transparent thermoplastic material exposes the metal foil to view, giving the plastic strip a metal-like appearance.

Problems have been encountered in producing an acceptable thermoplastic encapsulated metal foil. The metal foil is easily scratched during production. Scratches ruin the appearance of the trim strip, and contribute to a high reject rate.

The plastic material must be relatively inexpensive, and easy to fabricate. The plastic used must have the proper combination of torsional resistance and flexibility to enable the trim strip to conform easily to the auto surface to which it is attached without causing delamination of the metal foil strip.

SUMMARY OF THE INVENTION The present invention provides a method and apparatus for producing a trim strip assembly. The trim strip assembly, according to the present invention, has a longitudinal thermoplastic base member, a superimposed strip, and a plastic top coating. The apparatus includes a die having three passageways for receiving the extruded base member, the superimposed strip and the plastic top coating.

Accordingly, an object of this invention is to provide an improved trim strip assembly.

A further object of this invention is to provide apparatus to produce a trim strip assembly in high volume production.

A still further object of this invention is to provide a trim strip assembly having a base member, a superimposed intermediate strip and a plastic top coating.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic plan view of an apparatus for producing a trim strip assembly, including extruding means;

3,780,152 Patented Dec. 18, 1973 A DESCRIPTION OF THE PREFERRED EMBODIMENT Preferred apparatus 10 shown in FIGS. 1-5 is used to produce a trim strip assembly 11 shown in FIG. '6. Referring to FIG. 6, the trim strip assembly 11, has a thermoplastic base member 12, a superimposed strip 13 and a plastic top coating 14.

Referring to FIG. 1, the apparatus 10 includes a first conventional extruder 15 and a second conventional extruder 16, both operatively connected to a die 17. Plastic material is introduced into the first extruder 15 through an inlet 18 to form the thermoplastic base member 12, as subsequently explained in more detail. The die 17 preferably has heating means 19. A supply reel 20 carries the strip material 13. The strip material 13 is fed from the reel 20 to the die 17. The thin plastic top coating 14, as subsequently explained in more detail, is placed over the strip material 13 superimposed on the base member 12, thereby forming the strip assembly 11.

A pair of opposed driven rollers 21, pull the trim strip assembly 11 from the die 17. The trim strip assembly 11 is cooled as it leaves the die 17 by means of cooling-air jets 22 and a cooling tank 23. A cut-01f means 24 is used to cut the trim strip assembly 11 into desired lengths.

Referring to FIGS. 3 and 4, the die 17 has a first passageway 25 through which the thermoplastic base member 12 is directed. The first passageway 25 intersects a second passageway 26, and extends to an outlet orifice. The first passageway 25 is partially bounded on one side by the lower surface 27 of a first divided 28. The second passageway 26 directs the superimposed strip 13 onto the thermoplastic base member 12. The second passageway 26 terminates at the apex 30 of the upper and lower surfaces 27 and 29 of the first divider 28. A third passageway 31 for directing the plastic top coating 14 onto the superimposed strip 13, intersects the second passageway 26 a short distance from the intersection of the first and second passageways 25 and 26. The third passageway 31 is partially defined by a second divider 32. One inner surface 33 of the divider 32 intersects the second passageway 26 at the termination of the third passageway 31. The intersection of the second and third passageways 26 and 31 is in a plane normal to both passageways.

Referring now to FIG. 2 and FIG. 3 thermoplastic material suitable for forming the base member 12 passes from the first extruder 15 into the first passageway 25 of the die 17. Thermoplastic material suitable for formation of the base member 12 must have the proper combination of torsional resistance and flexibility. Plastics such as cellulose propionate, cellulose butyrate and cellulose acetate butyrate, either unmodified or conventionally modified by combination with plasticizers such as long-chain aliphatic esters, aromatic esters, aromatic and aliphatic phosphates, stabilizers and colorants, which are normally used for the top coating 14 may also be successfully used in base member formation, along with polyethylene and other thermoplastics which are not necessarily compatible with the top coat material. Depending upon the styling desired, the thermoplastic base member may be colored, transparent or opaque.

3 Referring to FIG. 3 and FIG. 4, a metal foil strip 13 is shown being directed along the second passageway 26. The use of the metal foil strip 13 is conjunction with the transparent plastic coating 14, produces the trim strip assembly 11, which has a metal-like appearance. The superimposed strip 13 is not limited to a metal foil or metal strip, and may include thermoplastic compositions. Because metal, metal foil and thermoplastic strips are available in different colors and designs, with burnished or embossed surfaces, such strips may be color-coordinated to the automobile. A thermoplastic composition used as the superimposed strip 13, need not be compatible with the thermoplastic base member 12. Because of the design of the die passageways, the plastic top coating 14 helps to mechanically bond the superimposed strip 13 to the base member 12.

Referring now to FIG. 4, the intersection of third passageway 31 which directs the plastic top coating 14 onto the superimposed strip 13 is shown in greater detail. The plastic top coating 14 is directed onto the strip material 13 a distance less than 0.10 inch ahead of the location where the strip 13 is placed upon the base member 12. The forces resulting from the dynamic intersection of the base member 12 and the superimposed strip 13 tend to position the strip 13 against the top of the first passageway 25. If the strip 13 is metal, contact with the top surface of the passagaway 25, may wrinkle or scratch the strip 13. However, if the top coating 14 is placed on the strip 13 before the strip 13 comes into contact with the base member 12, as is shown in FIG. 3 and described above, the strip 13 is protected against scratching and wrinkling. If a thermoplastic material is used as the strip 13, instead of metal or metal foil, scratching and wrinkling problems are lessened.

The plastic top coating 14 can be formed of a material dissimilar to the base member 12. Since the top coating 14 and the base member 12 are in a state of relative flux at the time of joining, the pressure and the heat used in forcing the trim assembly 11 through the die produces a thermal sealing or fusion between the two plastic materials. If the thermoplastic base member 12 and the plastic top coating 14 are not compatible, i.e., in the sense that they are not capable of fusing together, the upper surface of the thermoplastic base member 12 may be formed with a key slot 34 as shown in FIG. 5. The plastic top coating 14 will flow into the key slot 34, forming a mechanical lock which will hold the superimposed strip 13 securely to the base member 12.

The plastic top coating '14 is formed of a suitable material that has good weather-resisting and wear-resisting qualities, and is formed as a thin film over the superimposed strip 13. Materials such as polyvinyl chloride and cellulose acetate propionate are satisfactory.

In operation, the thermoplastic base member 12 is formed by first extruder v15 and is moved along a first longitudinally extending, enclosed planar path partially bounded by the first passageway 25. The strip material 13 is fed from a supply reel 20, and is directed along a second longitudinally extending enclosed planar path bounded by the upper surface 29 of a first divider 28. The second path is in a plane which intersects the first path in a line such that the line of intersection is normal to the direction of movement of both paths. The plastic top coating 14 is moved along a third enclosed path partially bounded by a second divider 32. The plastic top coating 14 is directed onto the strip material 13 at a predetermined distance from the intersection of the strip 13 and the base member 12. The trim strip assembly 11 which includes the thermoplastic base member 12, the superimposed strip 13 and the plastic top coating 14, is directed through an orifice, pulled from the die 17, and cooled.

What I claim is:

1. A method for forming a decorative trim strip assembly having a strip of a different material interjacent a thermoplastic top coating and a thermoplastic base member, said method comprising:

(a) extruding a thermoplastic base member by moving a thermoplastic base material along a first longitudinally extending, planer path and to and from an orifice which forms the base member,

(b) directing a strip of a different material along a second longitudinally extending, planar path, the second path being in a plane which defines an acute angle with such planar path and which intersects the first path,

(c) extruding a transparent compatible thermoplastic top coating upon said strip and said base member by moving a thermoplastic coating material along a path and onto said strip at a point on such strip path which is located a distance less than about 0.10 inch before the intersection of said strip and said base member, whereby such transparent top coating retards scratching of the upper surface of said strip, and from thence through an orifice which forms the coating, and

(d) cooling said trim strip assembly.

2. A method as claimed in claim 1 in which the top coating is applied to said strip a distance of from about .001 to .06 inch from the intersection of said strip and said base member.

3. A method as claimed in claim 1 in which the top coating is applied to said strip a distance of about .015 inch from the intersection of said strip and said base member.

4. A method as claimed in claim 1 in which the thermoplastic base member is selected from the group consisting of cellulose acetate and cellulose acetate butyrate.

5. A method as claimed in claim 1 in which the thermoplastic base member is cellulose acetate butyrate.

6. A method as claimed in claim 1 in which the top coating is selected from the group consisting of polyvinyl chloride and cellulose acetate propionate.

7. A method as claimed in claim 1 in which the top coating is polyvinyl chloride.

8. A method as claimed in claim 1 in which the upper surface of the thermoplastic base member contains a key slot, whereby the top coating is mechanically locked to the base member.

References Cited UNITED STATES PATENTS 3,551,542 12/1970 Perrone 264-174 3,136,676 6/1964 Fisch 264-174 FOREIGN PATENTS 857,814 l/l961 Great Britain 264-171 ROBERT F. WHITE, Primary Examiner T. E. BALHOFF, Assistant Examiner US. Cl. X.R. 156-244; 264-177 

